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<H1 align="center">SQL-运算符</H1>
<P align="right" 
style="margin: 0px 10px 0px 0px; padding: 0px;">最后修改时间：2016-05-11 11:14:06</P>
<HR style="border-width: 2px; border-color: lime;">

<P 
style="text-align: justify; background-color: rgb(255, 255, 255);">运算符是一个保留字或字符，主要用于在SQL语句的WHERE子句来执行，比较和算术运算等操作。 
</P>
<P style="text-align: justify; background-color: rgb(255, 255, 255);">
运算符用于指定一个SQL语句中的条件，并作为连词多个条件在一份声明中。 </P>
<UL style="text-align: left; background-color: rgb(255, 255, 255);">
  <LI>
  <P style="text-align: justify;">  算术运算符   </P></LI>
  <LI>
  <P style="text-align: justify;">  比较操作符   </P></LI>
  <LI>
  <P style="text-align: justify;">  逻辑运算符   </P></LI>
  <LI>
  <P style="text-align: justify;">  运算符用来作为否定条件   </P></LI></UL>
<H2 style='text-align: left; font-family: Helvetica, Arial, "Liberation Sans", FreeSans, sans-serif; font-size: 16px; background-color: rgb(255, 255, 255);'>SQL算术运算符： 
</H2>
<P style="text-align: justify; background-color: rgb(255, 255, 255);">
假设变量的一个持有值为10，变量b持有20： </P>
<TABLE width="100%" style="border: 1px solid rgb(170, 170, 170); border-image: none; width: 552px; text-align: left; color: rgb(0, 0, 0); font-size: 12px; background-color: rgb(241, 241, 241);" 
border="1" cellspacing="0" cellpadding="5">
  <TBODY>
  <TR>
    <TH width="10%" style="border: 1px solid rgb(170, 170, 170); border-image: none; background-color: rgb(205, 205, 205);"> 
           操作符       </TH>
    <TH width="45%" style="border: 1px solid rgb(170, 170, 170); border-image: none; background-color: rgb(205, 205, 205);"> 
           描述       </TH>
    <TH style="border: 1px solid rgb(170, 170, 170); border-image: none; background-color: rgb(205, 205, 205);"> 
           例子       </TH></TR>
  <TR>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;">+ 
            </TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;">加法 
      -添加任一侧上的操作符的值       </TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;">a 
      + b 得到&nbsp;30       </TD></TR>
  <TR>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;"> 
           -       </TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;">减法 
      - 从左边<SPAN style="background-color: rgb(241, 241, 241);">减去右边<SPAN style="background-color: rgb(241, 241, 241);">操作数的</SPAN></SPAN>操作 
            </TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;">a 
      - b <SPAN style="background-color: rgb(241, 241, 241);">得到</SPAN><SPAN 
      style="background-color: rgb(241, 241, 241);">&nbsp;</SPAN> -10       
  </TD></TR>
  <TR>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;"> 
           *       </TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;">乘法 
      - 操作符<SPAN style="background-color: rgb(241, 241, 241);">两侧</SPAN>的值相乘     
        </TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;">a 
      * b <SPAN style="background-color: rgb(241, 241, 241);">得到</SPAN><SPAN 
      style="background-color: rgb(241, 241, 241);">&nbsp;</SPAN> 200       
  </TD></TR>
  <TR>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;"> 
           /       </TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;">除 
      - 将左边除<SPAN style="background-color: rgb(241, 241, 241);">以右边</SPAN>的操作数   
          </TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;">b 
      / a <SPAN style="background-color: rgb(241, 241, 241);">得到</SPAN><SPAN 
      style="background-color: rgb(241, 241, 241);">&nbsp;</SPAN> 2       </TD></TR>
  <TR>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;"> 
           mod<BR></TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;">取模 
      - 没有%操作符，使用mod(a,b)代替<BR></TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;">mod(a,b) 
      得到 10<BR></TD></TR></TBODY></TABLE>
<H2 style='text-align: left; font-family: Helvetica, Arial, "Liberation Sans", FreeSans, sans-serif; font-size: 16px; background-color: rgb(255, 255, 255);'>
SQL比较操作符： </H2>
<P style="text-align: justify; background-color: rgb(255, 255, 255);"><SPAN 
style="background-color: rgb(255, 255, 255);">假设变量的一个持有值为10，变量b持有20：</SPAN> </P>
<TABLE width="100%" style="border: 1px solid rgb(170, 170, 170); border-image: none; width: 552px; text-align: left; color: rgb(0, 0, 0); font-size: 12px; background-color: rgb(241, 241, 241);" 
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  <TBODY>
  <TR>
    <TH width="10%" style="border: 1px solid rgb(170, 170, 170); border-image: none; background-color: rgb(205, 205, 205);"><SPAN 
      style="line-height: normal; font-weight: bold; background-color: rgb(205, 205, 205);">操作符</SPAN> 
            </TH>
    <TH width="45%" style="border: 1px solid rgb(170, 170, 170); border-image: none; background-color: rgb(205, 205, 205);"><SPAN 
      style="line-height: normal; font-weight: bold; background-color: rgb(205, 205, 205);">描述</SPAN> 
            </TH>
    <TH style="border: 1px solid rgb(170, 170, 170); border-image: none; background-color: rgb(205, 205, 205);"><SPAN 
      style="line-height: normal; font-weight: bold; background-color: rgb(205, 205, 205);">例子</SPAN> 
            </TH></TR>
  <TR>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;">= 
            </TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;">检查如果两个操作数的值是相等或不相等，如果是的话，条件为真。 
            </TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;">(a 
      = b) is not true.       </TD></TR>
  <TR>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;"> 
           !=       </TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;">检查如果两个操作数的值是否相等，如果值不相等，则条件为真。 
            </TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;">(a 
      != b) is true.       </TD></TR>
  <TR>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;"> 
           &lt;&gt;      </TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;">检查如果两个操作数的值是否相等，如果值不相等，则条件为真。 
            </TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;">(a 
      &lt;&gt; b) is true.       </TD></TR>
  <TR>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;"> 
           &gt;      </TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;">检查<SPAN 
      style="background-color: rgb(241, 241, 241);">值，</SPAN>如果左操作数大于右操作数的值，如果是的话，条件为真。 
            </TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;">(a 
      &gt; b) is not true.       </TD></TR>
  <TR>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;"> 
           &lt;      </TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;">检查如果左操作数的值小于右操作数的值，如果是的话，条件为真。 
            </TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;">(a 
      &lt; b) is true.       </TD></TR>
  <TR>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;"> 
           &gt;=       </TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;">检查如果左操作数的值大于或等于右操作数的值，如果是的话，条件为真。 
            </TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;">(a 
      &gt;= b) is not true.       </TD></TR>
  <TR>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;"> 
           &lt;=       </TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;">检查如果左操作数的值小于或等于右操作数的值，如果是的话，条件为真。 
            </TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;">(a 
      &lt;= b) is true.       </TD></TR>
  <TR>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;"> 
           !&lt;       </TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;">检查如果左操作数的值不小于右操作数的值，如果是的话，条件为真。 
            </TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;">(a 
      !&lt; b) is false.       </TD></TR>
  <TR>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;"> 
           !&gt;       </TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;">检查如果左操作数的值是不大于右操作数的值，如果是的话，条件为真。 
            </TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;">(a 
      !&gt; b) is true.       </TD></TR></TBODY></TABLE>
<H2 style='text-align: left; font-family: Helvetica, Arial, "Liberation Sans", FreeSans, sans-serif; font-size: 16px; background-color: rgb(255, 255, 255);'>
SQL逻辑运算符： </H2>
<P style="text-align: justify; background-color: rgb(255, 255, 255);">
这是在SQL所有的逻辑运算符的列表。 </P>
<TABLE width="100%" style="border: 1px solid rgb(170, 170, 170); border-image: none; width: 552px; text-align: left; color: rgb(0, 0, 0); font-size: 12px; background-color: rgb(241, 241, 241);" 
border="1" cellspacing="0" cellpadding="5">
  <TBODY>
  <TR>
    <TH width="20%" style="border: 1px solid rgb(170, 170, 170); border-image: none; background-color: rgb(205, 205, 205);"><SPAN 
      style="line-height: 18px; font-weight: normal;">运算符 </SPAN>       </TH>
    <TH width="80%" style="border: 1px solid rgb(170, 170, 170); border-image: none; background-color: rgb(205, 205, 205);"><SPAN 
      style="line-height: 18px; font-weight: normal;">描述 </SPAN>       </TH></TR>
  <TR>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;"><SPAN><SPAN><SPAN><SPAN><SPAN><SPAN>ALL</SPAN> 
      </SPAN> </SPAN> </SPAN> </SPAN> </SPAN>       </TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;"><SPAN><SPAN><SPAN><SPAN><SPAN><SPAN>所有运算符用于比较的值到另一个值组中的所有值。</SPAN> 
      </SPAN> </SPAN> </SPAN> </SPAN> </SPAN>       </TD></TR>
  <TR>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;"><SPAN><SPAN><SPAN><SPAN><SPAN><SPAN>AND</SPAN> 
      </SPAN> </SPAN> </SPAN> </SPAN> </SPAN>       </TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;"><SPAN><SPAN><SPAN><SPAN><SPAN><SPAN>AND运算符允许多个条件的存在，在一个SQL语句中的WHERE子句。</SPAN> 
      </SPAN> </SPAN> </SPAN> </SPAN> </SPAN>       </TD></TR>
  <TR>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;"><SPAN><SPAN><SPAN><SPAN><SPAN><SPAN>ANY</SPAN> 
      </SPAN> </SPAN> </SPAN> </SPAN> </SPAN>       </TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;"><SPAN><SPAN><SPAN><SPAN><SPAN><SPAN>ANY运算符用于比较的值在列表中根据任何适用的条件。</SPAN> 
      </SPAN> </SPAN> </SPAN> </SPAN> </SPAN>       </TD></TR>
  <TR>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;"><SPAN><SPAN><SPAN><SPAN><SPAN><SPAN>BETWEEN</SPAN> 
      </SPAN> </SPAN> </SPAN> </SPAN> </SPAN>       </TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;"><SPAN><SPAN><SPAN><SPAN><SPAN><SPAN>BETWEEN运算符用于搜索一组值的范围内的值，给定的最小值和最大值。</SPAN> 
      </SPAN> </SPAN> </SPAN> </SPAN> </SPAN>       </TD></TR>
  <TR>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;"><SPAN><SPAN><SPAN><SPAN><SPAN><SPAN>EXISTS</SPAN> 
      </SPAN> </SPAN> </SPAN> </SPAN> </SPAN>       </TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;"><SPAN><SPAN><SPAN><SPAN><SPAN><SPAN>存在指定的表中符合特定条件的运算符用于搜索存在的一行记录。</SPAN> 
      </SPAN> </SPAN> </SPAN> </SPAN> </SPAN>       </TD></TR>
  <TR>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;"><SPAN><SPAN><SPAN><SPAN><SPAN><SPAN>IN</SPAN> 
      </SPAN> </SPAN> </SPAN> </SPAN> </SPAN>       </TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;"><SPAN><SPAN><SPAN><SPAN><SPAN><SPAN>IN操作符用来比较的文字值已指定一个值的列表。</SPAN> 
      </SPAN> </SPAN> </SPAN> </SPAN> </SPAN>       </TD></TR>
  <TR>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;"><SPAN><SPAN><SPAN><SPAN><SPAN><SPAN>LIKE</SPAN> 
      </SPAN> </SPAN> </SPAN> </SPAN> </SPAN>       </TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;"><SPAN><SPAN><SPAN><SPAN><SPAN><SPAN>LIKE运算符用于比较相似的值，使用通配符的值。</SPAN> 
      </SPAN> </SPAN> </SPAN> </SPAN> </SPAN>       </TD></TR>
  <TR>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;"><SPAN><SPAN><SPAN><SPAN><SPAN><SPAN>NOT</SPAN> 
      </SPAN> </SPAN> </SPAN> </SPAN> </SPAN>       </TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;"><SPAN><SPAN><SPAN><SPAN><SPAN><SPAN>NOT运算符的含义相反的逻辑运算符，它被使用如 
      NOT EXISTS, NOT BETWEEN, NOT IN 等，这是一个相反的运算符。 </SPAN> </SPAN> </SPAN> 
      </SPAN> </SPAN> </SPAN>       </TD></TR>
  <TR>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;"><SPAN><SPAN><SPAN><SPAN><SPAN><SPAN>OR</SPAN> 
      </SPAN> </SPAN> </SPAN> </SPAN> </SPAN>       </TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;"><SPAN><SPAN><SPAN><SPAN><SPAN><SPAN>使用OR运算符结合SQL语句的WHERE子句中的多个条件。</SPAN> 
      </SPAN> </SPAN> </SPAN> </SPAN> </SPAN>       </TD></TR>
  <TR>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;"><SPAN><SPAN><SPAN><SPAN><SPAN><SPAN>IS 
      NULL</SPAN> </SPAN> </SPAN> </SPAN> </SPAN> </SPAN>       </TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;"><SPAN><SPAN><SPAN><SPAN><SPAN><SPAN>NULL操作符用来比较NULL的值。</SPAN> 
      </SPAN> </SPAN> </SPAN> </SPAN> </SPAN>       </TD></TR>
  <TR>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;"><SPAN><SPAN><SPAN><SPAN><SPAN><SPAN>UNIQUE</SPAN> 
      </SPAN> </SPAN> </SPAN> </SPAN> </SPAN>       </TD>
    <TD style="border: 1px solid rgb(170, 170, 170); border-image: none; vertical-align: top;"><SPAN><SPAN><SPAN><SPAN><SPAN><SPAN>独特的操作符搜索指定的表中的每一行的唯一性（不重复）。</SPAN> 
      </SPAN> </SPAN> </SPAN> </SPAN> </SPAN></TD></TR></TBODY></TABLE>
<H3>运算符的优先级</H3>
<P style="text-indent: 0.8cm;">运算符的优先级别如下表中所示:优先级由高到低<BR></P>
<TABLE responsive="true">
  <TBODY>
  <TR responsive="true">
    <TH>
      <P><SPAN class="sentence" id="mt6" data-guid="c9e9a848920877e76685b2e4e76de38d" 
      data-source="Level" xml:space="preserve"><sentencetext xmlns="http://www.w3.org/1999/xhtml">Level</sentencetext></SPAN></P></TH>
    <TH>
      <P><SPAN class="sentence" id="mt7" data-guid="0997fb356c249146ffe97cce96f88459" 
      data-source="Operators" xml:space="preserve"><sentencetext xmlns="http://www.w3.org/1999/xhtml">运算符</sentencetext></SPAN></P></TH></TR>
  <TR>
    <TD data-th="Level">
      <P><SPAN class="sentence" id="mt8" data-guid="c4ca4238a0b923820dcc509a6f75849b" 
      data-source="1" xml:space="preserve"><sentencetext xmlns="http://www.w3.org/1999/xhtml">1</sentencetext></SPAN></P></TD>
    <TD data-th="运算符">
      <P><SPAN class="sentence" id="mt9" data-guid="5e0e0f1f1a08171ffc3ddc416e7833d5" 
      data-source="~ (Bitwise NOT)" xml:space="preserve"><sentencetext xmlns="http://www.w3.org/1999/xhtml">~（位非）</sentencetext></SPAN></P></TD></TR>
  <TR>
    <TD data-th="Level">
      <P><SPAN class="sentence" id="mt10" data-guid="c81e728d9d4c2f636f067f89cc14862c" 
      data-source="2" xml:space="preserve"><sentencetext xmlns="http://www.w3.org/1999/xhtml">2</sentencetext></SPAN></P></TD>
    <TD data-th="运算符">
      <P><SPAN class="sentence" id="mt11" data-guid="7d56ce04be72138af836228e88c7a268" 
      data-source="* (Multiply), / (Division), % (Modulo)" 
      xml:space="preserve"><sentencetext 
      xmlns="http://www.w3.org/1999/xhtml">*（乘）、/（除）、%（取模）</sentencetext></SPAN></P></TD></TR>
  <TR>
    <TD data-th="Level">
      <P><SPAN class="sentence" id="mt12" data-guid="eccbc87e4b5ce2fe28308fd9f2a7baf3" 
      data-source="3" xml:space="preserve"><sentencetext xmlns="http://www.w3.org/1999/xhtml">3</sentencetext></SPAN></P></TD>
    <TD data-th="运算符">
      <P><SPAN class="sentence" id="mt13" data-guid="7a931adf4211b0ad2651cc47d957db76" 
      data-source="+ (Positive), - (Negative), + (Add), (+ Concatenate), - (Subtract), &amp;amp; (Bitwise AND), ^ (Bitwise Exclusive OR), | (Bitwise OR)" 
      xml:space="preserve"><sentencetext 
      xmlns="http://www.w3.org/1999/xhtml">+（正）、-（负）、+（加）、（+连接）、-（减）、&amp;（位与）、^（位异或）、|（位或）</sentencetext></SPAN></P></TD></TR>
  <TR>
    <TD data-th="Level">
      <P><SPAN class="sentence" id="mt14" data-guid="a87ff679a2f3e71d9181a67b7542122c" 
      data-source="4" xml:space="preserve"><sentencetext xmlns="http://www.w3.org/1999/xhtml">4</sentencetext></SPAN></P></TD>
    <TD data-th="运算符">
      <P><SPAN class="sentence" id="mt15" data-guid="7ca456fd4a6646c85c16e43a55b85e4e" 
      data-source="=, &amp;gt;, &amp;lt;, &amp;gt;=, &amp;lt;=, &amp;lt;&amp;gt;, !=, !&amp;gt;, !&amp;lt; (Comparison operators)" 
      xml:space="preserve"><sentencetext xmlns="http://www.w3.org/1999/xhtml">=, 
      &gt;, &lt;, &gt;=, &lt;=, &lt;&gt;, !=, !&gt;, !&lt; 
      （比较运算符）</sentencetext></SPAN></P></TD></TR>
  <TR>
    <TD data-th="Level">
      <P><SPAN class="sentence" id="mt16" data-guid="e4da3b7fbbce2345d7772b0674a318d5" 
      data-source="5" xml:space="preserve"><sentencetext xmlns="http://www.w3.org/1999/xhtml">5</sentencetext></SPAN></P></TD>
    <TD data-th="运算符">
      <P><SPAN class="sentence" id="mt17" data-guid="d529e941509eb9e9b9cfaeae1fe7ca23" 
      data-source="NOT" xml:space="preserve"><sentencetext xmlns="http://www.w3.org/1999/xhtml">NOT</sentencetext></SPAN></P></TD></TR>
  <TR>
    <TD data-th="Level">
      <P><SPAN class="sentence" id="mt18" data-guid="1679091c5a880faf6fb5e6087eb1b2dc" 
      data-source="6" xml:space="preserve"><sentencetext xmlns="http://www.w3.org/1999/xhtml">6</sentencetext></SPAN></P></TD>
    <TD data-th="运算符">
      <P><SPAN class="sentence" id="mt19" data-guid="be5d5d37542d75f93a87094459f76678" 
      data-source="AND" xml:space="preserve"><sentencetext xmlns="http://www.w3.org/1999/xhtml"><sentencetext 
      xmlns="http://www.w3.org/1999/xhtml">And</sentencetext> 
      </sentencetext></SPAN></P></TD></TR>
  <TR>
    <TD data-th="Level">
      <P><SPAN class="sentence" id="mt20" data-guid="8f14e45fceea167a5a36dedd4bea2543" 
      data-source="7" xml:space="preserve"><sentencetext xmlns="http://www.w3.org/1999/xhtml">7</sentencetext></SPAN></P></TD>
    <TD data-th="运算符">
      <P><SPAN class="sentence" id="mt21" data-guid="316564973586bd24bc00f717f9846591" 
      data-source="ALL, ANY, BETWEEN, IN, LIKE, OR, SOME" 
      xml:space="preserve"><sentencetext 
      xmlns="http://www.w3.org/1999/xhtml">ALL、ANY、BETWEEN、IN、LIKE、OR、SOME</sentencetext></SPAN></P></TD></TR>
  <TR>
    <TD data-th="Level">
      <P><SPAN class="sentence" id="mt22" data-guid="c9f0f895fb98ab9159f51fd0297e236d" 
      data-source="8" xml:space="preserve"><sentencetext xmlns="http://www.w3.org/1999/xhtml">8</sentencetext></SPAN></P></TD>
    <TD data-th="运算符">
      <P><SPAN class="sentence" id="mt23" data-guid="acc8e660c13cc78fc6e4aed4a05cc44e" 
      data-source="= (Assignment)" xml:space="preserve"><sentencetext xmlns="http://www.w3.org/1999/xhtml">=（赋值）</sentencetext></SPAN></P></TD></TR></TBODY></TABLE>
<P 
style="text-indent: 0.8cm;">当一个表达式中的两个运算符有相同的运算符优先级别时，将按照它们在表达式中的位置对其从左到右进行求值。 
<BR></P>
<P style="text-indent: 0.8cm;"><SPAN 
style="color: rgb(255, 0, 0);">如果要提升运算的优先级，可以使用()小括号，如果小括号中有小括号，优先执行里面的小括号中的运算。</SPAN><BR></P>
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